Virological Investigation Of Enteroviruses From Healthy Children In The Border Areas Of Yunnan Province,2012

Objectives To virological investigate the healthy children under15years old who came from border areas with Myanmar in Yunnan province of2012, to analysis the genetic characteristics of enteroviruses, to strengthen the surveillance of acute f laccid paralysis (AFP) and to consolidate the achievement s of Polio-free status in Yunnan province.Methods A total of300stool samples were collected from healthy children in the10enterance ports.Enterovirus were isolated from these stool samples and then poliovirus was serotyped by neutralization test using specific anti-sera. The partial sequences of the non-polio enterovirus (NPEVs) were successfuLly amplified by Reverse Transcription-Polymerase Chain Reaction(RT-PCR) and were compared with other enterovirus isolated available from GenBank.Results All19entervirus were isolated from300stool samples and6.33%of them carried the virus.1poliovirus was isolated with rate of0.33%.The resuLts of NPEVs sequencing showed that:2islate(10.5%) were classified into HEV-A,17islates(89.5%) were classified into HEV-B,1islate(5.3%) was classified into HEV-C,HEV-D and new type enterovirus were not isolated.The homogeneity analysis showed that the nt and aa identification between isolates and corresponding standard strains were more then75%and88%,the findings were similar to the international standards. Phylogenetic tree based on VP1sequence from EV71indicates the subtype is C4a.The calcuLation of distance between groups showed that the difference rate of nt between group was17.2%-20.3%of ECHO19,and the calcuLation of distance between CB1isolates and prototype showed that the difference rate of nt was18.8%, The calcuLation of distance between groups showed that the difference rate of nt between group was the calcuLation of distance between groups showed that the difference rate of nt between group was13.3%-22.4%of ECH013, The operation of AFP surveillance system in9counties of border areas of Yunnan in2012were analyzed. and the reporting rate is more thanl/100thousand except gengma county and longchuan county.Conclusions Our resuLts showed that HEV-B group appeared the predominant with the wide spread of enterovirus serotype in border areas with Myanmar in Yunnan province of2012,HEV-D,new type enterovirus and wild poliovirus were not isolated,that means we also contain the no-polio status. According to analyze the subtype gene of EV71,we knew that the subtype gene of EV71was C4a, The phyloginetic analysis of3strains of ECHO19showed the genetic diversity of E19in Yunnan province,and the same genotype can exist in different regions and different time for a long time.The genetic type of Yunnan and Shandong isolates were the same,which were different from the prototype strain.The phyloginetic analysis showed that the genetic diversity of E13of the worldwide. The operation of AFP surveillance system in border counties was good, and the surveillance indicators attained the WHO standards.